The invention relates to a device for the production of an anaerobic, micro-aerophilic or similar type of atmosphere in a closed interchangeable container including a lid. The container can be connected to a unit to provide the desired atmosphere inside the container for the incubation of micro-organisms inside the container. Such atmospheres are known to be required in microbiology, medicine, pharmacology and in research for the cultivation of anaerobic, micro-aerophilic and other micro-organisms. For this purpose, laboratory samples (on nutrient mediums in Petri dishes) are placed in the interchangeable container, which is subsequently inserted in an aperture of the unit provided. This automatically attaches the interchangeable container to the unit and establishes the desired atmosphere by program-controlled evacuation and gassing. Following the end of the program, the interchangeable container is removed from the device and placed in a warming cupboard for incubation to proceed.
In the case of the xe2x80x9cAnoxomatxe2x80x9d described in the prospectus xe2x80x9cMART systemsxe2x80x94a standard for microbiology throughout the worldxe2x80x9d, a control device is described for the partial automation of the type of gassing and evacuation specified above. This control device is provided with free connecting tubes to which a vessel can be attached for the production of the anaerobic atmosphere. The corresponding connecting elements are provided as manual coupling parts on the lid of the vessel. Several cables, connecting tubes and connecting elements are provided for the control system, vacuum pump and gas cylinders, which results in a complicated handling procedure. In addition, the vacuum pump, which is not integrated in the control unit, must be set up somewhere on the outside. Thus, there is a danger of faulty operation as a result of the use of the wrong connecting tubes and/or incorrectly connecting these elements. Furthermore, the xe2x80x9ctemporaryxe2x80x9d connecting tubes and cables and/or the manually-connected elements of the vessel lid and control unit as well as the vacuum pump are exposed and, as a consequence, highly susceptible to damage.
The present invention is based on the need to eliminate these disadvantages and to create a device of the nature specified in the introduction, in which a mobile interchangeable container containing the laboratory samples can be inserted simply, rapidly and reliably in the aperture of a static unit, and a desired atmosphere can subsequently be produced in the interior of the interchangeable container without any appreciable manual labor.
The invention solves this problem by providing elements to automatically connect and disconnect a gas supply unit to an interior of an interchangeable container. The elements form an alternating system for creating the desired atmosphere inside the container by evacuating and gassing.
In one very advantageous version, a static unit is provided with an integrated vacuum pump, various gas connections, gas valves, and a vacuum-operated docking cylinder. The interchangeable container is attached, gas-tight, by the docking cylinder, and the interchangeable container is evacuated and gassed once or several times in accordance with a program until the desired atmosphere has been established in the interior of the interchangeable container.
In the device of the invention, it is only necessary to bring the interchangeable containers containing the laboratory samples into the aperture provided in the unit and then to push the start button. This is followed by fully automatic coupling, evacuation and gassing for the establishment of the desired atmosphere without any manual activity. The process reliability of the device is also guaranteed by the fact that no tubes or manual coupling elements are present and that, in the case of the docking cylinder, gas is supplied through an internal channel. There are also no protruding connecting elements on the interchangeable container. This gives rise to the advantage that the interchangeable containers can be stacked and thus stored in the warming cupboard in a manner that saves a great deal of space. Furthermore, the vacuum-operated docking cylinder facilitates a simple and space-saving method of construction of the static unit.
It is an advantage if, in accordance with the invention, the docking cylinder is formed of a cylinder piston unit, wherein a cylinder is fixed to the device and the piston has, on the side of the interchangeable container, a docking attachment that can be moved against a coaxial pressure spring. The docking cylinder is provided, at the front, with a sealing ring that can be pressed against the lid of the interchangeable container. The piston, including the piston ring and docking attachment, is fitted with an internally continuous channel for the evacuation and supply of gas. As a result of this construction, the docking cylinder requires almost no maintenance and offers process reliability.
In order to facilitate the seizure and handling of the interchangeable container, the invention provides for the interchangeable container to be made of lightweight material (polycarbonate, aluminum) and for vertical ribs to be arranged over its circumference.
In order to achieve as simple and maintenance-free closure of the interchangeable container as possible, the invention also provides for the lid of the interchangeable container to be fitted with a bayonet catch. The catch is expediently provided with a lip seal on the inner edge of the interchangeable container and has, in the middle of the closure, in the position of the docking cylinder, gas inlet and outlet channels, in which a back-pressure valve is installed in each instance.
The invention also provides for the floor of the interchangeable container to be provided with a recess at its center that corresponds with a correspondingly constructed elevation in the lid of the interchangeable container. In this way, the interchangeable containers can be centered and simply stacked on top of one another.